Fiber reinforced plastic (FRP) materials are widely used in aerospace industry due to its high specific strength and high specific stiffness. FRP materials are composite materials consisting of soft resin matrix and high strength fiber reinforcement. Typical fiber reinforcements include carbon fibers (CFRP), glass fibers (GFRP), Kevlar fibers, and the like. FRP materials are often processed into a laminated structure. FRP materials have excellent in-plane strength, but low inter-laminar strength.
Multi-function end effectors, portable orbital machines and CNC machines produce orbital (helically interpolated) holes and/or conventionally drilled holes in composite stack materials.
The major issue of machining composite stack materials is the accelerated wear that occurs on the tool edges. Tool life is very poor, even with advanced substrates and coatings.